Serum selenium and glutathione peroxidase-3 activity: biomarkers of systemic inflammation in the critically ill?

ABSTRACT

OBJECTIVES: To confirm the influence of systemic inflammatory response syndrome (SIRS) on selenium (Se) levels and prospectively evaluate the relationship between serum Se concentration [Se], glutathione peroxidase activity [GPx-3] and injury severity in patients at the time of intensive care unit (ICU) admission. DESIGN: Prospective, observational study. SETTING: Multidisciplinary University Hospital ICU. PATIENTS AND PARTICIPANTS: A total of 36 ICU patients and 23 healthy volunteer subjects (HVS). MEASUREMENTS AND RESULTS: Healthy volunteer subjects were designated as controls (Group 1). ICU patients were divided into three groups without SIRS (Group 2); with SIRS (Group 3); with SIRS and multiple organ dysfunction syndrome (MODS) (Group 4). The latter groups had APACHE II scores >15. [GPx-3] and [Se] were determined by standard methods within the first 48 h of admission to ICU. Kruskal-Wallis and Mann-Whitney U test were used for analysis of non-parametric continuous variables. The predictive value of [Se] and [GPx-3] for SIRS was calculated using a receiver operating characteristics (ROC) analysis. In SIRS and MODS patients [GPx-3] and [Se] decreased significantly (P = 0.0001 and P = 0.002, respectively). After ICU admission [GPx-3] and [Se] had a predictive value for SIRS ([GPx-3] sensitivity 90%, specificity 86.2% (cut-off value 0.5 U/mL); [Se] sensitivity 90%, specificity 72.4% (cut-off value 60 microg/L). [Se] had predictive value for ICU mortality (P = 0.034). CONCLUSIONS: Systemic inflammatory response syndrome and MODS were associated with early decreases in [Se] and [GPx-3]. Low [Se] and [GPx-3] after ICU admission had a predictive value for SIRS, which may aid future selection of patients who could benefit from Se supplementation.